FAA proposes fuel tank fixes to cut explosion risk

Aloha Air operates one of the jet models that would be affected

Star-Bulletin staff and news services

WASHINGTON » U.S. airlines would have to modify fuel tanks on jet aircraft to reduce the risk of explosions like the one that downed TWA Flight 800 in 1996, under rules being proposed by the Federal Aviation Administration.

The proposed changes affect 3,200 existing planes and new airliners at a cost of $808 million over 49 years, the FAA said in a statement today. Boeing Co. 737 and 747 models and Airbus SAS A320s will be retrofitted first, the agency said.

Aloha Airlines, which operates 21 737s, has yet to assess the costs the proposed modifications would require, according to spokesman Stuart Glauberman.

"There's no way to tell how or even whether this will affect us," he said yesterday. "Once they decide what they want us to do, then we would have to comply with it."

The modifications would have to be done on existing jets within seven years, and those retrofits would cost $313 million, the FAA said. The rest of the cost is for installing systems on future aircraft, as well as expenses for engineering and for operating the systems over the 49-year period, the agency said.

The FAA in February 2004 said it would propose a rule later that year to reduce explosion risks. The National Transportation Safety Board in July said the FAA was taking too long to issue the rule.

The proposed rule aims to reduce the possibility that fuel-tank vapors will ignite, as the Washington-based agency tries to avoid a repeat of the TWA explosion and three others since 1989 that resulted in a combined 346 deaths.

The safety board concluded that the explosion of TWA Flight 800 off Long Island, New York, was caused by ignition of a flammable fuel-air mixture. The ignition source probably was an electrical short circuit that let excessive voltage enter the fuel tank through wiring of a fuel-quantity indicator, the board said.

All 230 people aboard the Boeing 747 TWA flight died. The three other tank explosions were also Boeing models, including an Avianca 727 in 1989, a Philippine Airlines 737 in 1990 and a Thai Airways International Pcl 737 in 2001.

The rule would prevent four explosions over 50 years, the FAA estimated. The agency also estimated that one explosion in a Boeing 747 or Airbus A380 would cost at least $1.2 billion.

One solution under the rule is to install a device that pumps nitrogen into tanks to reduce flammability. The FAA said it will also consider "other means" that carriers and airlines propose to comply with the rule. The agency plans to take comments for four months.